Process of and apparatus for burning cement.



B. E. ELDRED.

PROCESS OF AND APPARATUS FOR BURNING CEMENT.

' APPLICATION FILED 111 11.30, 190s. RENEWED APR. 8, 1909.

928,51 3. Patented Jul 20. 1909.

'- 4SHEETS-BHEBT 1.

B. E. ELDRED. PROCESS OF AND APPARATUS FOR BURNING CEMENT. APPLICATION FILED APR. 30, 1908. RENEWED APR. 8, 1909.

Patented 1July 20, 1909.

@BHEETB-BHEET 2.'

' vwentoz B. E. ELDRED. PROCESS OF AND APPARATUS FOR BURNING CEMENT. APPLIUATION FILED APR. 30, 1903. RENEWED APR. 8, 1909.

Patented July 20, 1909.

4 SHEETS-SHEET 3.

Suva n for I than,

B. E. ELDRED. PROCESS OF AND APPARATUS FOR BURNING 0E APPLIQATION IILEDAPR. 30

, 190B. RENEWED APR. 8, 1909.

I Z m m T 0 mm W QE 3 .W m uE m 4 m n m P 3 1 5 ,v 8 2 9 till- BYRON E. ELD RED, OF llllOilXVlllLli, NEW XORK, A SSIGNOR TO THE l lld'lllll il) 64, PALlll'E I l COMPANY, OF NEW fill- K 1 Y A CORPOllAllON OF NEW YORK.

Implication 11 ed April 30, 1998, Serial No. $30,183. Ilimanewcwi April 8, 1909.

tipesifiezltion of Letters; Fatent.

Patent-ed July 220, 1809,

Serial, No. 4133,7313.

llu it. known that l, BYRON F. i"

t'lllfitll til the lfllltctl lmmx "villa. in the iJ-Oiinty ki'ltiitcs, and

t'll'nlu of New York, have invented. cmrlziin m. and Apparatus: lbr

c'llll'll as will enable others; sliiiliwl in the 2127i:-

l which it up crhilns tr) umhc til process cement; and 0mm tmnpmrutuiv are ulinlwi'vil in a ikutnty slink tine liml huniiiig withllhv gitl'nm'ntivi-lly hezilml h the \Yilh'tt) heat (ll titlltl iilinlmring kiln; tlllll it tum zu'lnxptctl :lm NHL, in the shit like PUXTPHSOS; all as 1110,

ln the prior art it l'ltl pmrlk n the. val-mus an.

30 1] uuetmnairy to (1 diverse reactions (ll'lt'fllll'lllg in the ctimunt kiln with thaw raid in"? :1 singlu stimuli of he t:

huge, volume at heat but (1005 not med. a

wry high tlzagi'ce at ten utlwr, the 1.:li1ilmrii'1p' p np lmitc 'l' qllllellwll form both these rczicli sourci- 0t limit. inevitably fuel. li, a prim patent .l 1900, l have 'tltlmrihml i ixei'aitim'o While til1- resentsl Exactly the The effort t0 pair" 011% with 11 singh; leads to :1 Waste of No. 829,956, Elcpt a, method 0f obvitih in this waste and securing a number of new advantages, said method tinl'ly in tliviiiling the cal consisting SlibS'lLZU)" iii-mt milk] 11; {l gamlion into stages 41nd perfm'ining each stage in a separate kiln with the source of heat, each stage being perliormml aid, of a separate u'mlm thermal and other cm'lditiim s heal;

nlaptml thereto. F illrilfii. t -Qpt. 4. 1906,}

In another patent, No.

have described and lt\llll((l (*vitain organizations of apparatus 21ml similar plftll? of and lll lll, 1 have: llE-Slillllfid tint chilitietl certain the gases t'mi iiaipiuiting heat to assist in clinker lug. There is hmvm'm' 2m uhjectinn to the llr-llfl 0t prmlucci' Qtln in this (.Ollfltftfllllll in that mmmvhnl: more fuel is required than (l1ll'ttEKJ'0lHlH t0 the natural ifequlmniali'ts 0t thn .iitvm'ntiun. lit a -linl et-ing hill: operating l my LB-stage PL'FWQSS? th s thui'miil conditions are almost slat The c: l f'llltb wmw lulu it l l'flllt the c-alcinii'lgg' kiln heated la, 01' nhmmt to the Rimming lfiilll'ltlliltlllt} and in the tlinltvl'iilgg reacliom that is:- the unitm (if the lime o l the alcines "with silica and alumina,littlem'im heat is absorbed While some is ei olvctll The only i'equii't-zim-mt m) the rrl'lizlmiing lillll is that it quickly luring; those ttllt'lllQtl up to the clinhei'ing teinpe'zttnre and maintain the CfllClHQS zit fillflll tempe tm'o until the art-actioncompletes itself. The heat mquired for this is pi'nhahly m'urlml- WlHlT'QL l lay the limit emlved in the rem-than.

The 0i: impurtunt heat hassles of the (linkt l'lngl; hihl are those time, to mtliation and t0 littlt carried away by the finished (linker.

producer {gas used in the mannm' set Faith in the acknowledged patents will give the required amount of heat and temperature cheaply and conveniently .but it snliers several disadvantages, one being that a certain traction of the heat. must be carried away with the products of combustion from the kiln unless the regenerators be also employed to heat other air or gas than that employed in the kiln itself. This is for the reason that for every atom of oxygen used in the producer (or volume ct air) to pro duce gas another atom (or volume of air)- must be used to burn this gas. That is, for every volume ot air used in the producer another volume o'l air must be used to burn the resultant gas. The products of combustion formed have the same volume (at the same temperature) as the airnsed; the amount of such products is equal to the sum of the volumes of the air used in the producer and the air used in burning the gas. 'lhcret'ore, there will be (negflecting expansion and tempe 'ature) two volumes of products of combustiongoing thrt'iugh the regenerator for every volume of air coming back through the regenerate! to be heated, and only half the heat units can be utilized in the regenerator it' it be employed to heat only the air used in the kiln.

it is the object of the present invention to obviate even this source of loss of heat in the performance of my described Q-stage cement burning process, and to this end, i

rearrange the conditions somewhat and heat the clinker kiln with a flame of tine 'Fuel, ureter-ably coal dust though oil may be used, turning in aerial suspension with the aid of hot air regeneratively heated from the waste gases of such kiln. burning carbon does not change in volume, apart from temperature changes, one volume, or molecule, of O uniting with one (I to form one volume, or molecule, of CO That is, air used in burning carbon will. have the same volume afterward as before it brought back to the same temperature; and in the case of the clinker kiln heated. by burning carbon, the volume. of. products'of combustion will be nearly the same as that of the air used in burning, and a rce'enerator may be used without the theoretical stated loss of heat. in practice, of course some.- what of an excess of air over theory must be used to secure quick and intense combus- ..tion, but. this excess appears unchanged in -the products of combustion.

In heating: the clinkerine' kiln with a flame of fine fuel in this, as in other embodiments of my Q-stage process, regenerators may be safely employed since the calcines do not. give olT dust in the clinkering kiln to any important extent. in the operation ot the ordinary llI, {'l(-lil't(l rotar v, the raw cement material, which is always very finely powdered undergoes a tumultuous evolution oi? carbon di- 'lheoretically, air in.

oxid in the calcining Zone and this, in connection with the inordinate rush of gases caused by maintenance of a clinkering flame in the same kiln, causes the waste. gases to be heavily laden with dust.

The requirement for heat units in the clinkering kiln being so small when the clinkering kiln is run in connection with a separate calciningkiln, and the heat units being ctl'ectivcly recovered in the regenerator, very little coal is required for heating and the tlame employed may he correspondingly small, being merelya short thin llame in lieu of the very long, thick and violent tiame oi the ordinary single kiln practice. With this short, thin [tame the temperature may be very accurately adjusted; something not possible with the violent tlames of the single kiln practice. its position in the kiln may be as desired: axial, impinging 'or. merely inclined. it may be tempered with products of combustion or steam, but this is ordinarily not desirable or useful.

It being ditiicult to introduce the full amount of air necessary for combustion with the fuel since the fuel cannot be well evenly distributed through such a volume, I prefer to introduce the n'lainbulk of the-heated air beside or around the coal jet, introducing merely a portionwith the jet. This has the fur her advantage that, with such hot air as l contemplate using, coking ot' the coal dust in the injecting nozzle is prevented.

With air introduced at a temperature corresponding; to that of the clinkering kiln, or the waste gases tlu-re't'rom, the combustion of the coal is extremely quick and the temperatures developed are extremely high. Ulii'ikering takes place under temperatures which ordinarily range around 2500 l.*., or

'higher. This quick burning, high temperature t'lame enables me to maintain the desired type of small, thin flame and to meet the requirements of the clinkering kiln with very little expenditure of fuel. The amount of coal so used being so-smali, naturally I do: not contaminate the clinker with any noticeable. amount 0i ash-a great desideratum in this art. Air being introdm-tal into the kiln under pressure while the regenerators oppose a frictional resistance to the outward passage, of productsot' combustion the kiln may be easily run under a slight plenum which prevents access of cold air. .\s sta ed, the demands for heat. units in the. clinkering kiln are largely to compensate tor leakage losses and it is highly desirable to prevent such access of cold air aside from the derangement of conditions which such air may cause. be very slight.

'lhe calcining kiln operated "in connectionwith the clinkeriup; kiln may be gas tired or coal tired, but however heated it should be so controlled that. calcnu-s are ordinarily de The. plenum should howeverv cined however,

- seriloed.

on necessity for e advantages oi? my a very small lame "heated en- .pitfel. it s provided with the usual housing provided with a "neeeie livered to the elinkerer in state oi incipient from pipe the demand. for

eintering, thereby reducing I The colheet units in the clinhering kiln. nines should be free, or SllbSttUltiillly so, ol carbon dioxid. ll: the caleines he well callthe temperature at which they are delivered to the elinherer is not of grout moment and the point of incipient elinlvering may swing heel; and 'l'iorth hot-ween the two kilns. lt-

this look of delizute balancing of conditions" between the c: l cining and :linl er-- inn zones which otters one oi the greatest. Q-lciln process are coir struoted Withthe prior art in which one source olihent was used for both zones.

ll ith' the cement material well calcined, there is no great liability of dusting and when it is at the pointo1" inclpicnt sinte ring or softening it of course does not dust. at: till.

it is this which constitutes thernu n reason :tor p1 fer-ring that the or leines he introduced inti') the clinker kiln in a stage of incipient endering. But since. the clinker kiln under the present invention is run with and little rush of thnne there is little liability of much dusting in any event. Calcination l1o'\vev .r is preternbly completed in the :alcining kiln since evolution of carbon dioxid requires it. goo l volume of heat, and a pleutrl'nl supply ot' diluent gases to sweep it away; neither be ing; conditions existing in the clinker kiln under the present invention.

lo the zrceompenying drawings 1' have illnst-reted, more or less ding'annneticelly,

certain embodiments of my invention as; do

ln this ring:--llignre 1 a view, n'roslxly .i vertical longitudinal section, of 21 complete clinker plant; Fig. a plan view, partly in horizontal section, oi": the clinlterer of Fig. 1 gll igi is :1 similar view of a modification; and .liig. 4. is a VlQW of another modification.

lln Fig. 1, element 1 designates e calcining ltiln, liragmentarily and diagrannnntically shown. As represented, it is provided with gnF-diring menus 2, drawing a supply of through conduit '3 from u cliulter duct (5 forremoval of enlciner. From this duct, the eulcines drop .into n hopper 'l' and are fed forward into the clinlceringlziln by conveying means 8 passing through the back wall 9 of clinlzering kiln l0 substantiallylike that shown in my l ntent l 0. 879.448. lnthis kiln the eelcinesheeome clinkered and finally emerge tli'eretrom, dropping through conduit l1 into a, clinker pit. l acing the open mouth ol the hiln is a housing l2 carrying thefirlug; means... Theijse consist, as shown, of a coal burning nozile, l3, fed with powdered fuel from hopper H and air under pressure the blast. side ll. conitoinec'l "jet nozzle 1.6 in this pipe allows the air to carry the C'Ottl forward by induction. ()n either side oi thin burner is n. tlue, respectively 17 and 18, emnmunicnting with regeiieretors 1t) and 20 (see Fig. In Fig. 1, flue 18 (not shown) comnnuticetes with downteke 21 having dust 1 door 22 at its lease and uptake 23, tapped at. 2- to permit withdrawal oi a portion o'l heated air to feed fan 25 (see Fig. 2) through valved pipe 26; fr similar pipe 27 taps the iuiitnlge from flue 17. F or the sake of simplieity both these pipes ire shown provided with hand valves. A valved inlet. 28 permits the supply of cool air to the fun to temper the hot air from the regenol ator tines. On

of the fan is u pipe 15 communicating with thehuruer as already do scribed i 4 Returning to regenerzrl'or All, this is provided with the usual checlmrworlr .29. The other .regenern'tor, 19, isthe some in structure. Both regeueretors are provided With-a. p: e sage 550 leading, to steel: 31, post. lnutertlv valve ot the usual C(lllfitlUClllOll.

The operation of the dee ihed strwst-ure obvious. It being the object to produce :1 relatively small. intensely hot Home in the clinker kiln, the coal lalast is fed with hot eintuken from the regeneretor which heat.- ing air, its tei'ruperntnre being regulated if necessary by admission of a little cool air from 28. But a. fraction of the air necessary burn the coal however can he sent. in with it. in this manner and the residue 'e introduced from flue 17 or tlue ltl, according to which regenerntor is in the air heating;

rind the hot lhnne gases recurve and. sweep hock throughthe other hie end into :iud through. the other regeneretor, renting; it up, and ultimately to the starch.

lln the organization shown in l igs. 9., the calcining kiln is gns'tired, end the clinheror is coal fired. llhe gas employed for tlmculeiner may udvzultngeouely he producer g, e and the hot air employed to burn it may nclvmtageously be somewhat. diluted with prmlucts of combustion, since producer gas and hot air give a. shorter {hone than is advantageous in calcirmtious. The firing" in this kiln should he so controlled that, the :sleines emerge at or near the clinker-inn temperature since this reduces the consumption of fuel 'in the clinkereri should be as free as possible of carbon di, oxid since this interferes with the normal operation oztthe clinherer.

Fig. 3 shows, partly in horizontal section and partly view of a clinkerer fired by a coal jet in the manner described. in this structure, the

1 and .cliukerer 40 in lieu of being," the-peculiar ltiln of my former patent. is built like on ordi- Such culci nes,

in plan, a rather diagrammatic nary rotaryi Atits lower end it enters an ordinary housing 41 pierced for admission of coal burner pipe 42, fed from hopper 43, and for hot air ducts 44. At its upper end, it is provided with means for introducing calcines, shown in dotted lines at a5, and enters a stationary housing a6. From this housing pass outward two similar flues 47 and 48, co trolled by water-cooled valve a9, shown as closing 4". These twh tines enter regenerators, respectively 50 and 51, near the top thereof. At the base of the regeneratois fines 52 and lead to stack 54, being controlled dampers 55 and 56. Tapped into these fines are valved air ducts 57 and 58 deriving air from blower 59. Tapped into the fines LT and 4-8 are air conduits 60 and 61 leading to the lmrningmeans ot' the kiln. By appropriate manipulation of the valves, the hot waste gases can be sent through either flue, 47 or 48, into the corresponding regenerator, heating it up and passing thence to the stack while the other regenerator can have air passed throii'g'h it to conduit 44.

Fig. ll shows diagrammatically, the co'nibi nation of a calciner coal fired by burner 71, ted by hopper 72 and fan 73, with a clinkerer Tel, calcines being delivered to the latter through hopper T5 and conveyer '70 delivering into hopper T7 having a conduit 78 leading down through a housing 79 at the upper end of the clinker kiln, said housing being provided with stack 80 for removal of waste gases. Atthe lower end of the clinkt-rrer is the usual housing 8L, pierced for coal burner 52, fed by hopper 83and fan 8 t. As statcd, the consumpton ot' fucl'in the clinkering kiln in operating a plant according to my process, isvery little and, as shown. in this ligurc, regenerative means may be dispensed with for the coal-fired clinkercr.

- Use or such regenerative means is, however,

advantageous.

' in the operation of the clinkcrcr shown in Fig. l, the coal is burned in air altcrmitively entering at one side and at the other, there by somcwhat changing the localization of the intcnsc con1lui.-tion. i rom the conditions existing in thc kiln. this makes little ditl'crcncc lint it' it he desired. \vhcn the valvcs oi the rcgcncrators arc rcvcrscd and tlic place of cntry ol' llll hot air is changcd lhc dircction ot rotation ol' the kiln can also he rcvcrscd.

\l'hilc thc calcining kiln may lac coal-tired, as shown in l ig. l. vcl l rcgard it as prct'cralilc to heat it with gas as gas hcating islict ll'l' adaptcd to calcining conditions. prodnccr gas and hot. air. particularly it' the air lic soon-what dilutcd with products of combustion. a llanivparticularly adaptcd to calcination ma v he obtained. With coal tir ing means very inlcnsc tcmpcratnrcs arc apt to bc attained, and these arc not desirable in With l I l the calcining kiln in the present invention since it is the object to transfer the hightemperature operations toithe special c1inkering kiln. In the calcining kiln it is desirable to do no substantial amount of clinker mg though the materials should emerge from it thoroughly calcined and substantially tree from carbon dioxid, and, preferably, at or near the point of incipient clinkcrmg.

The use of gas in thewcalciner and of coal in the clinkerer enables a very good and eX-- act production of the diil'erent thermal conditions in the two kilns: the gas producing a ditl'uscd heating at comparatively low tem )erature for calcining and a little coal jet urningwith superheated air enalolin the production of the few heat units an hi h temperature of the cliukerer.

that I claim is i. A clinker making plant comprising a rotary separately fired calcining kiln and a rotary clmkering kiln provided with means for burning finely divided concentrated ifuel therein by the aid of air regeneratively heated by the 'aste gases of uch clinkering kilna 2. ii clinker making plant compris ng a rotary separately fired calcining kiln and a rotary clinkering kiln provided with means for producing therein a relatively small flame of powdered coal in aerial suspension. burning with the aid of air regencratively hea ted by the waste gases of such clinkering kiln.

A clinker making plant comprising a rotary clinkering kiln, means for introducing calcined cement material at the point of incipient clinkering thereinto, lmeans for producing a jet of fine fuel in aerial 'suspension in such kiln, waste gas removing means for such kiln, rcgenerators interposed between the kiln and waste gas removing means and means for passing air through such regcncrators into proximity with such jet 0F fine iuel.

l-. A clinker making plant comprising means .t'or producing calcined cement material at or near the clinkering point, a rotary clinkering kiln reccivingsuch calcined material. mcans for producing a lame jet of fine t'ucl in aerial suspension in the mouth of' such kiln. regenerative means for producing a current of hot air on one side of such flame and rcgcncrative mcaus removing waste gas-cs at the other side of Such flame.

.i. A clinkcr making plant comprising mcans for producing calcined material at or ncar tlic clinkcrm-g' temperature. a rotary cliukcring kiln having a closed upper end,..1 25

lncans for introducing said calcined mate rial into such uppcr cud, mcans for feeding v a jct oi' powdcrcd coal into the lower cnd. a pair oi 'rcgcncrators having tines opening into said lowcr cud on cithcr side of said therefrom.

rotary calcining -or near the point of incipient clinkermg,

material at or near the clii'ikering coal tired clinkering kiln receiving calcines H. A clinker making plant comprising a rotary calcining kiln provided with means for firing the sanie'with gas and hot air and a rotary clinkering kiln receiving calcines theretrom and provided with means for tin ing with tine fuel in aerial suspension and heated air.

$3. The process of producing cei'n'ent-clinker which comprises producing calcined cement point by a separate source of heat, transferring such calcined material to a rotary cement kiln and there completing the clinkering by a tlame jet of tine fuel in aerial suspension burning with the aid of air regcneratively heated by the waste gases of such' kiln.

lthlhe. process of. producing cement clinker which comprises passing pulvernlent cement material through a separately fired kiln to produce calcines at transferring such calcines to another rotary kiln and there completing the clinkering by a. flame jet of fine coal in aerial suspension.

11.. The process of producing cement clinker which comprises passing pnlverulent cement material through a gas tired rotary calcining kiln to produce calcines at or near the point of incipient clmkernig, transferring such oalcines to another rotary kiln and there completing the clinkering by a flame jet of powdered coal burning in aerial suspenslon. i

IQHThe process of producing cement clinker which comprises passing pulverulent cement material through a gas tired rotary calcining kiln to produce calcines at. or near the point ot.incipient clinkering, transferring such calcincs to another rotary kiln and there completing the clinkering by a flamejet of powdered coal burning in aerial sus pension with the aid of air regeneratively heated hy the waste gases of such second kiln.

i l. The process of producing cement clinker which comprises producing calcined cement material at or near the point. of incipient clinkering by one source of heat. .transl errmg said calcined material to a rotar; kiln and there completing the clinkering by arecurying tlame of powdered coal in aerial suspension burning with the aid of regeneratively heated air. 1

l-l. The process of producing cement clinker which comprises producing calcined cement material at or near the point. of incipient clinkerinp by one source of heat,

-transterring such calcined material to a rotary kiln, introducing a jet of tine coal in aerial s-aus 'iension into the mouth of said kiln, introducing a current of heated a." at one side of said jet to burn said coal and removing the waste tlame gases at the. other side of said jet. and removing the clinker from said kiln after ctnnpletion ot' the. clinkering. lit. in a clinker making plant, means for producing calcines a rotary kiln receiving calcines therefrom, means for supplying calcined cement materials thereto, means for producing a tlamc of line fuel in aerial sus pension in the mouth of the ki n and regene 'ative means abstracting heat. from the waste gases from such flame and returning it to air ted to such tlame.

In testimony whereof I atlix my signature in the presence of two witnesses.

BYRON F. ELDRED. Witnesses K. P. Mol lnaor, A. M. QJENIOR. 

